Being out of breath when you exercise could be a sign of a problem with your main artery, the aorta – according to new research from the University of East Anglia.

It was previously thought that breathlessness while exercising was a sign of heart or lung problems, or being generally unfit.
But a new study reveals that as people get older, the way that blood is carried away from the heart to the rest of the body through the aorta becomes less efficient.
This is associated with a decrease in the ability to exercise, which is why some people may have difficulty breathing during physical activities.
The team hope their work could open new avenues for diagnosis and treatment.
Lead researcher Prof Pankaj Garg, from UEA’s Norwich Medical School, said: “Shortness of breath is a normal symptom during intense exercise or exertion, particularly for people who are overweight or not usually very active.
“When patients present with symptoms of shortness of breath, doctors usually think of the heart or lungs as the main cause.
“We wanted to find out whether there might be another cause.”
The team investigated the main artery that carries blood away from the heart to the rest of your body, known as the aorta.
They studied a group of 169 healthy people with a broad range of ages, with no heart problems.  
Using advanced MRI imaging techniques, they measured how blood flowed in the aorta while the participants did exercise tests.
Prof Garg said: “Our study shows that the way blood flows through the aorta is connected to how efficiently our body uses energy when we exercise. If the blood flow in the aorta is smooth and steady, it helps us use our energy better while working out.
“We also found that as people grew older, the way blood flowed in their aorta became less effective and more turbulent – like a bumpy road. When the blood flow is not smooth, it can make our body less effective at using energy during exercise.
“This is the first time that an association of reduced exercise capacity with changes to blood flow in the aorta, has been discovered.
“Our work reveals a new cause of shortness of breath during exercise, particularly where usual tests have failed to pick up a cause in the heart or lungs.
“If you ever feel out of breath, it might be because of the way your blood is flowing in your aorta.
“If the flow is not right, it can make it harder for your body to get the oxygen it needs when you're active. So, unusual blood flow in the aorta could be one reason why you might feel short of breath.
“Studying this helps doctors understand how to keep our hearts and bodies healthy.
“We hope that our discovery could lead to a better understanding of why some people experience difficulty breathing during physical activities - and potentially open new avenues for diagnosis and treatment.”
This study was a collaboration between UEA and the national Heart Centre Singapore, along with other international experts.
‘Aortic flow is associated with aging and exercise capacity’ is published in the European Heart Journal.